Change-speed transmission

ABSTRACT

A change-speed transmission comprises: an input member; an output member; a planetary gearing unit; a hydrokinetic unit having a pump connected to the input member for simultaneous rotation therewith and a turbine; and first, second and third clutches. The transmission has a condition in which all of the torque of the input member is transmitted to the output member through the hydrokinetic unit, a condition in which all of the torque of the input member is transmitted to the output member bypassing the hydrokinetic unit, and a condition in which a portion of the torque of the input member is transmitted to the output member bypassing the hydrokinetic unit and the remaining portion of the torque of the input member is transmitted to the output member through the hydrokinetic unit.

BACKGROUND OF THE INVENTION

The present invention relates to change-speed transmissions and moreparticularly to an automatic transmission using a hydrokinetic unit,such as a torque converter, followed by a planetary gearing unit.

The conventional automatic transmission of the above type has thefollowing advantages when used in an automobile:

(1) The hydrokinetic unit insures smooth and effortless start-up of theautomobile;

(2) It insures shockless shifting even when the accelerator is keptdepressed;

(3) It absorbs mechanical vibration derived from variations of torque ofthe engine; and

(4) It lengthens the life span of the associated planetary gearing unit.

However, the automatic transmission has the following disadvantages:

(1) It causes the associated engine to consume more fuel than ifequipped with a manual transmission, and;

(2) It has a sluggish response to demand for engine braking.

In an attempt to alleviate these disadvantages, there has been proposedan automatic transmission having a hydraulic torque converter with atleast one clutch and planetary gear set combination in which torque ofthe engine is split and transmitted through two flow paths. In thisprior art automatic transmission, the direct drive or bypass clutch isselectively operable to interconnect the pump of the hydraulic torqueconverter and the turbine thereof for simultaneous rotation therewith tothereby bypass the torque converter and eliminate slippage in thetransmission. In other words, the torque can be transmitted eithertotally through the torque converter, or directly, but nothing inbetween. In a second prior art transmission, a gearing unit has a rotaryelement connected to the turbine of the torque converter, and the pumpis connected to another rotary element so that the input torque of theengine is at all times transmitted through two flow paths, one includingthe torque converter, and the other including the other rotary element.In this arrangement, the hydrokinetic unit cannot be totally bypassed.

A disadvantage with the first prior art automatic transmission mentionedabove resides in that the fuel economy during all low and middle speedoperating is still compromised. The economy is bad because under theseoperations conditions, the direct clutch is disengaged and the hydraulictorque converter delivers the full torque from the engine to the gearingunit. Another disadvantage is that over a given range of speed ofrotation, the variation of torque of the engine is great. This isespecially undesirable during the middle and relatively high speedranges after the direct clutch has been engaged. As the automobile slowsdown in these ranges, the engine tends to start "lugging" causing arough driving condition and undue wear on the engine. In the secondmentioned prior art transmission, the shortcoming arises because overalloperating conditions, ranging from low speed operation to high speedoperation, a portion of torque is always transmitted from the engine tothe gearing unit through the torque converter. Thus, the overall fueleconomy leaves much to be desired due to the slip of the torqueconverter in the high speed operation.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide, for thepurpose of alleviating the disadvantages encountered in the prior art, achange-speed transmission which takes the best of the two prior arttransmissions, thereby giving the optimum fuel economy. The transmissionof the present invention is not limited to the "all or nothing"condition of the first mentioned prior art transmission since in themiddle speed ranges a split of the torque is obtained. By the sametoken, 100 percent direct drive can be obtained in the highest speedratio, not just partial direct drive, as found in the second describedprior art transmission.

Thus, in the transmission of the present invention, all of the enginetorque is effected through a hydrokinetic unit to provide smoothstart-up of an automobile from standstill. Secondly, the transmissionhas a condition in which the transmission of all (100%) of the enginetorque is effected bypassing the hydrokinetic unit for maximum economy.And, finally, a condition exists in which the transmission of the enginetorque is effected through a split along a first flow path including thehydrokinetic unit and through a second flow path bypassing thehydrokinetic unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described hereinafter in connection with theaccompanying drawings, in which:

FIGS. 1-12 are schematic diagrams of various embodiments of a changespeed transmission of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the first embodiment of the invention, in which thereference numeral 1 indicates an input shaft, the reference numeral 2 anoutput shaft, and between the input shaft and output shaft 1 and 2,three planetary gear sets X, Y and Z are arranged with their axesaligned.

The first planetary gear set X is a basic or simple planetary gear setconstructed of a first sun gear S₁, a first ring gear R₁ and a firstcarrier A₁ rotatably supporting a plurality of pinions P₁ each meshingthe sun gear S₁ and ring gear R₁.

The secondary planetary gear set Y is a dual-intermeshed planet pinionplanetary gear set constructed of a second sun gear S₂, a second ringgear R₂ and a second carrier A₂ rotatably supporting a plurality ofpairs of intermeshing pinions P₂ and P₂ '. Each pinion P₂ meshes withthe sun gear S₂, while each pinion P₂ ' meshes with the ring gear R₂.

The third planetary gear set Z is a dual-intermeshed planet pinionplanetary gear set, similar to the second planetary gear set Y,constructed of a third sun gear S₃, a third ring gear R₃ and a thirdcarrier A₃ rotatably supporting a plurality of pairs of intermeshingpinions P₃ and P₃ '. Each pinion P₃ meshes with the sun gear S₃, whileeach pinion P₃ ' meshes with the ring gear R₃.

In the first planetary gear set X, the following equation holds.

    N.sub.R1 +α.sub.1 N.sub.S1 =(l+α.sub.1)N.sub.A1 (1)

In the second planetary gear set Y, the following equation holds.

    N.sub.R2 -α.sub.2 N.sub.S2 =(l-α.sub.2)N.sub.A2 (2)

In the third planetary gear set Z, the following equation holds.

    N.sub.R3 -α.sub.3 N.sub.S3 =(l-α.sub.3)N.sub.A3 (3)

where, N_(R1), N_(R2) and N_(R3) denote the number of rotations of ringgears of planetary gear sets X, Y and Z, respectively.

N_(S1), N_(S2) and N_(S3) denote the number of rotations of sun gears ofthe planetary gear sets X, Y and Z, respectively.

α₁, α₂, and α₃ denote the ratio of number of teeth of a sun gear tonumber of teeth of a ring gear of the planetary gear sets X, Y and Z,respectively.

The transmission according to the invention comprises an input shaft 1supplying the input torque, a hydraulic torque converter 3 having a pump3a connected to the input shaft 1 for simultaneous rotation therewithand a turbine 3b connected to the second carrier A₂ for simultaneousrotation therewith. First sun gear S₁ and second sun gear S₂ areconnected to each other for simultaneous rotation and are connectable,for simultaneous rotation, to second carrier A₂ through a first clutchC₁ and brakeable by a first brake B₁. First carrier A₁ is brakeable by asecond brake B₂ and first ring gear R₁ and third ring gear R₃ are bothconnected to output shaft 2 to provide one path for the output torque.Second ring gear R₂ is connected to third sun gear S₃ for simultaneousrotation therewith. Third carrier A₃ is connectable to the input shaft 1through a second clutch C₂. A third clutch C₃ is operable to connect thethird carrier A₃ to the output shaft 2 and the ring gears R₁, R₃ foranother path for the output torque.

The operating sequence of the three clutches C₁, C₂ and C₃ and twobrakes B₁ and B₂ are tabulated in Table 1, in which legend o denotes theengagement condition of a clutch or applied condition of a brake. In theTable 1 reduction gear ratio and the direct transmission rate, i.e., therate of a portion of torque transmitted through second clutch C₂bypassing torque converter 3 to all of the torque of input shaft 1, arecalculated on the assumption that α₁ =0.35, α₂ =0.40 and α₃ -0.45.

                  TABLE 1                                                         ______________________________________                                                                                     Direct                                                                        Trans-                                                                        mission                                                                Gear   Rate                             C.sub.1 C.sub.2                                                                             C.sub.3                                                                             B.sub.1                                                                           B.sub.2       Ratio  (%)                              ______________________________________                                        1st                                                                           speed             o       o                                                                                  ##STR1## 3.571  0.0                            2nd                                                                           speed       o             o                                                                                  ##STR2## 1.847  67.1                           3rd                                                                           speed       o         o                                                                                      ##STR3## 1.220  67.1                           4th                                                                           speed       o     o           1.0       1.000  100.0                          Rev.  o                   o                                                                                  ##STR4## -2.857 0.0                            ______________________________________                                    

Referring to FIGS. 2 through 12, the other embodiments of the inventionwill be described hereinafter. In these embodiments, like referencenumerals and characters to those used in FIG. 1 are used to denote likecomponent parts. Since the same or similar function is being carried outin each instance by the parts with like references, no additional ordistinguishing identification is necessary or desirable.

In the second embodiment shown in FIG. 2, a first planetary gear set Xis a dual-intermeshed planet pinion planetary gear set which has a firstsun gear S₁, a first ring gear R₁ and a first carrier A₁ rotatablysupporting a plurality of pairs of intermeshing pinions P₁ and P₁ '.Each pinion P₁ meshes with the sun gear S₁, while each pinion P₁ 'meshes with the ring gear R₁. Second and third planetary gear sets Y andZ shown in FIG. 2 are dual-intermeshed planet pinion planetary gear setssimilar to those shown in FIG. 1.

In planetary gear set X of this embodiment, the following equationholds.

    N.sub.R1 -α.sub.1 N.sub.S1 =(l-α.sub.1)N.sub.A1 (4)

In the second and third planetary gear sets Y and Z of this embodiment,equations (2) and (3) hold.

The transmission of FIG. 2 comprises an input shaft 1 providing theinput torque, a hydraulic torque converter 3 which has a pump 3aconnected to the input shaft 1 for simultaneous rotation therewith and aturbine 3b connected to first sun gear S₁. First sun gear S₁ isconnectable to a second sun gear S₂ through a first clutch C₁ and thesecond sun gear S₂ is brakeable by a first brake B₁. First carrier A₁ isconnectable to input shaft 1 through a second clutch C₂, and also tooutput shaft 2 through a third clutch C₃ providing one output torquepath. First ring gear R₁ is connected both to second carrier A₂ andthird sun gear S₃ for simultaneous rotation therewith. Second ring gearR₂ and third carrier A₃ are connected to each other for simultaneousrotation and they are brakeable by means of a second brake B₂. Thirdring gear R₃ is connected to output shaft 2 creating another outputtorque path.

The operating sequence of three clutches C₁, C₂ and C₃ and two brakes B₁and B₂ of the FIG. 2 transmission is tabulated in Table 2 on theassumption that α₁ =α₂ =0.40 and α₃ =0.50.

                  TABLE 2                                                         ______________________________________                                                                                     Direct                                                                        Trans-                                                                        mission                                                                 Gear  Rate                             C.sub.1 C.sub.2                                                                             C.sub.3                                                                             B.sub.1                                                                           B.sub.1        Ratio (%)                              ______________________________________                                        1st                                                                           speed             o       o                                                                                  ##STR5##  3.500 0                              2nd                                                                           speed       o             o                                                                                  ##STR6##  2.000 60                             3rd                                                                           speed       o         o                                                                                      ##STR7##  1.250 60                             4th                                                                           speed       o     o           1.0        1.000 100                            Rev.  o                   o                                                                                  ##STR8##  -3.000                                                                              0                              ______________________________________                                    

In the third embodiment shown in FIG. 3, first, second and thirdplanetary gear sets X, Y and Z are dual-intermeshed planet pinionplanetary gear sets similar to those shown in FIG. 2. Therefore,equations (4), (2) and (3) hold for these first, second and thirdplanetary gear sets, X, Y and Z respectively.

The transmission shown in FIG. 3 comprises an input shaft 1, a hydraulictorque converter 3 having a pump 3a connected to the input shaft 1 forsimultaneous rotation therewith and a turbine 3b connected to first sungear S₁ for simultaneous rotation therewith. First sun gear S₁ isconnectable to second sun gear S₂ through a first clutch C₁ and thesecond sun gear is brakeable by means of a first brake B₁. First carrierA₁ is connectable to input shaft 1 through a second clutch C₂ and alsoto output shaft 2 through a third clutch C₃ for a first output torquepath. First ring gear R₁ is connected both to second carrier A₂ andthird carrier A₃ for simultaneous rotation therewith. Second ring gearR₂ and third sun gear S₃ are connected to each other for simultaneousrotation and are brakeable by means of a second brake B₂. Third ringgear R₃ is connected to output shaft 2 for simultaneous rotation toprovide a second output torque path.

The operating sequence of three clutches C₁, C₂ and C₃ and two brakes B₁and B₂ of the transmission shown in FIG. 3 is tabulated in Table 3 onthe assumption that α₁ =α₂ =0.35 and α₃ =0.50.

                                      TABLE 3                                     __________________________________________________________________________                                           Direct                                                                        Trans-                                                                        mission                                                                  Gear Rate                                   C.sub.1 C.sub.2                                                                          C.sub.3                                                                          B.sub.1                                                                          B.sub.1          Ratio                                                                              (%)                                    __________________________________________________________________________    1st                                                                           speed      o     o                                                                                 ##STR9##     3.857                                                                              0                                      2nd                                                                           speed   o        o                                                                                 ##STR10##    2.000                                                                              65                                     3rd                                                                           speed   o     o                                                                                    ##STR11##    1.212                                                                              65                                     4th                                                                           speed   o  o        1.0           1.000                                                                              100                                    Rev. o           o                                                                                 ##STR12##    -3.714                                                                             0                                      __________________________________________________________________________

In the embodiment shown in FIG. 4, a first planetary gear set X and asecond planetary gear set Y are dual-intermeshed planet pinion planetarygear sets, similar to those shown in FIG. 3, while a third planetarygear set Z is a basic planetary gear set.

Therefore, equations (4) and (2) hold for the first and second planetarygear sets X and Y of this embodiment, respectively, while, for the thirdplanetary gear set Z, the following equation holds.

    N.sub.R3 +α.sub.3 N.sub.S3 =(l+α.sub.3)N.sub.A3 (5)

The transmission shown in FIG. 4 comprises an input shaft 1, a hydraulictorque converter 3 having a pump 3a connected to the input shaft 1 forsimultaneous rotation therewith and a turbine 3b connected to sun gearS₁ for simultaneous rotation therewith. Carrier A₁ and sun gear S₂ areconnected to each other for simultaneous rotation and are brakeable bymeans of a first brake B₁. Ring gear R₁ is connectable to carrier A₂through a first clutch C₁. This carrier A₂ is connectable to input shaft1 through a second clutch C₂. Ring gear R₁ and sun gear S₃ are connectedto each other for simultaneous rotation and are brakeable by a secondbrake B₂. Ring gears R₂ and R₃ are connected to each other forsimultaneous rotation and are connectable to input shaft 1 through athird clutch C₃. Carrier A₃ is connected to an output shaft 2 forproviding the output torque.

The operation sequence of three clutches C₁, C₂ and C₃ and two brakes B₁and B₂ of this transmission is tabulated in Table 4 on the assumptionthat α₁ =α₂ =α₃ =0.45.

                                      TABLE 4                                     __________________________________________________________________________                                        Direct                                                                        Trans-                                                                        mission                                                                  Gear Rate                                      C.sub.1 C.sub.2                                                                          C.sub.3                                                                          B.sub.1                                                                          B.sub.2       Ratio                                                                              (%)                                       __________________________________________________________________________    1st                                                                           speed                                                                              o        o                                                                                    ##STR13## 3.222                                                                              0                                         2nd                                                                           speed   o     o                                                                                    ##STR14## 1.927                                                                              73                                        3rd                                                                           speed      o  o                                                                                    ##STR15## 1.206                                                                              83                                        4th                                                                           speed                                                                              o  o  o        1.0        1.000                                                                              100                                       Rev. o           o                                                                                 ##STR16## -3.938                                                                             0                                         __________________________________________________________________________

In the fifth embodiment shown in FIG. 5, a first planetary gear set X isa dual-intermeshed planet pinion planetary gear set, while, second andthird planetary gear sets Y and Z are basic planetary gear sets.

Equations (4) and (5) hold for first and third planetary gear sets X andZ of the transmission, respectively, and for second planetary gear set Ythereof, the following equation holds.

    N.sub.R2 +α.sub.2 N.sub.S2 =(l+α.sub.2)N.sub.A2 (6)

This transmission comprises an input shaft 1, a hydraulic torqueconverter 3 having a pump 3a connected to the input shaft 1 forsimultaneous rotation therewith and a turbine 3b connected to sun gearS₁ for simultaneous rotation therewith. Carrier A₁ is brakeable by meansof a first brake B₁ and is also connectable to sun gear S₂ through afirst clutch C₁. This sun gear S₂ is connectable to input shaft 1through a second clutch C₂. Ring gear R₁, ring gear R₂ and sun gear S₃are connected to one another for simultaneous rotation and are brakeableby means of a second brake B₂. Carriers A₂ and A₃ and output shaft 2 areconnected to one another for simultaneous rotation to produce the outputtorque. Ring gear R₃ is engageable with input shaft 1 through a thirdclutch C₃.

The operation sequence of three clutches C₁, C₂ and C₃ and two brakes B₁and B₂ on the assumption that α₁ =0.40 and α₂ =α₃ =0.45 is shown inTable 5.

                                      TABLE 5                                     __________________________________________________________________________                                        Direct                                                                        Trans-                                                                        mission                                                                  Gear Ratio                                     C.sub.1 C.sub.2                                                                          C.sub.3                                                                          B.sub.1                                                                          B.sub.2       Ratio                                                                              (%)                                       __________________________________________________________________________    1st                                                                           speed                                                                              o        o                                                                                    ##STR17## 3.625                                                                              0.0                                       2nd                                                                           speed   o     o                                                                                    ##STR18## 1.706                                                                              52.9                                      3rd                                                                           speed      o  o                                                                                    ##STR19## 1.229                                                                              84.7                                      4th                                                                           speed   o  o        1.0        1.000                                                                              100.0                                     Rev. o           o                                                                                 ##STR20## -4.833                                                                             0.0                                       __________________________________________________________________________

In the sixth embodiment shown in FIG. 6, a first planetary gear set Xand a third planetary gear set Z are dual-intermeshed planet pinionplanetary gear sets, respectively, while, a second planetary gear set Yis a basic planetary gear set.

Equations (4), (6) and (3) hold for first, second and third planetarygear sets X, Y and Z of this transmission.

This transmission comprises an input shaft 1, a hydraulic torqueconverter 3 having a pump 3a connected to the input shaft 1 forsimultaneous rotation therewith and a turbine 3b connected to sun gearS₁ for simultaneous rotation therewith. Carrier A₁ is connectable to sungear S₃ through a first clutch C₁ and brakeable by means of a firstbrake B₁. Sun gear S₃ is connectable to input shaft 1 through a secondclutch C₂. Ring gear R₁, sun gear S₂ and carrier A₃ are connected to oneanother for simultaneous rotation and are brakeable by means of a secondbrake B₂. Ring gears R₂ and R₃ are connected to each other forsimultaneous rotation and are connectable to input shaft 1 through athird clutch C₃. Carrier A₂ is connected to an output shaft 2 forproviding the output torque.

The operating sequence of three clutches C₁, C₂ and C₃ and two brakes B₁and B₂ of this transmission is tabulated in Table 6 on the assumptionthat α₁ =α₃ =0.40 and α₂ =0.35.

                  TABLE 6                                                         ______________________________________                                                                                   Direct                                                                        Trans-                                                                        mission                                                                 Gear  Rate                               C.sub.1 C.sub.2                                                                             C.sub.3                                                                             B.sub.1                                                                           B.sub.2      Ratio (%)                                ______________________________________                                        1st                                                                           speed o               o                                                                                  ##STR21##   3.553 0                                2nd                                                                           speed       o         o                                                                                  ##STR22##   1.731 51                               3rd                                                                           speed             o   o                                                                                  ##STR23##   1.184 88                               4th                                                                           speed       o     o       1.0          1.000 100                              Rev.  o                                                                                                  ##STR24##   -5.062                                                                              0                                ______________________________________                                    

In the seventh embodiment shown in FIG. 7, a first planetary gear set Xand a second planetary gear set Y are dual-intermeshed planet pinionplanetary gear sets, respectively, while, a third planetary gear set Zis a basic planetary gear set.

Equations (4), (2) and (5) hold for first, second and third planetarygear sets X, Y and Z of this transmission.

This transmission comprises an input shaft 1, a hydraulic torqueconverter 3 having a pump 3a connected to the input shaft 1 forsimultaneous rotation therewith and a turbine 3b connected to sun gearS₁ for simultaneous rotation therewith. Carrier A₁ is brakeable by meansof a first brake B₁ and connectable to carrier A₂ through a first clutchC₁. The carrier A₂ is connectable to input shaft 1 through a secondclutch C₂. Ring gears R₁ and R₃ and sun gear S₂ are connected to eachother for simultaneous rotation and are brakeable by means of a secondbrake B₂. Carrier A₂ is connected to sun gear S₃ for simultaneousrotation therewith. Ring gear R₂ is connectable to input shaft 1 througha third clutch C₃, while, carrier A₃ is connected to output shaft 2 forsimultaneous rotation and production of the output torque.

The operating sequence of three clutches C₁, C₂ and C₃ and two brakes B₁and B₂ of the transmission shown in FIG. 7 is tabulated in Table 7 onthe assumption that α₁ =α₃ =0.45 and α₂ =0.60.

                                      TABLE 7                                     __________________________________________________________________________                                     Direct                                                                        Trans-                                                                        mission                                                                   Gear                                                                              Rate                                         C.sub.1                                                                             C.sub.2                                                                         C.sub.3                                                                         B.sub.1                                                                         B.sub.2          Ratio                                                                             (%)                                          __________________________________________________________________________    1st                                                                           speed                                                                             o     o                                                                                  ##STR25##     3.222                                                                             0                                            2nd                                                                           speed o   o                                                                                  ##STR26##     1.611                                                                             50                                           3rd                                                                           speed   o o                                                                                  ##STR27##     1.141                                                                             89                                           4th                                                                           speed o o     1.0            1.000                                                                             100                                          Rev.                                                                              o       o                                                                                ##STR28##     -3.938                                                                            0                                            __________________________________________________________________________

In the eighth embodiment shown in FIG. 8, a first planetary gear set Xis a dual-intermeshed planet pinion planetary gear set, while, secondand third planetary gear sets Y and Z are basic planetary gear sets,respectively.

Equations (4), (6) and (5) hold for first, second and third planetarygear sets X, Y and Z of this transmission, respectively.

This transmission comprises an input shaft 1, a hydraulic torqueconverter 3 having a pump 3a connected to the input shaft 1 forsimultaneous rotation therewith and a turbine 3b connected to sun gearS₁ for simultaneous rotation therewith. Carrier A₁ is brakeable by afirst brake B₁. Sun gears S₂ and S₃ are connected to each other forsimultaneous rotation and are connectable to carrier A₁ through a firstclutch C₁. These sun gears S₂ and S₃ are connectable to input shaft 1through a second clutch C₂. Ring gears R₁ and R₂ are connected to eachother for simultaneous rotation and are brakeable by a second brake B₂.Carrier A₂ and ring gear R₃ are connected to each other for simultaneousrotation and are connected to an output shaft 2 for simultaneousrotation and output torque production. Carrier A₃ is connectable toinput shaft 1 through a third clutch C₃.

The operating sequence of three clutches C₁, C₂ and C₃ and two brakes B₁and B₂ of the transmission shown in FIG. 8 is tabulated in Table 8 onthe assumption that α₁ =0.35 and α₂ and α₃ =0.45.

                                      TABLE 8                                     __________________________________________________________________________                                  Direct                                                                        Trans-                                                                        mission                                                                   Gear                                                                              Rate                                            C.sub.1                                                                             C.sub.2                                                                         C.sub.3                                                                         B.sub.1                                                                         B.sub.2       Ratio                                                                             (%)                                             __________________________________________________________________________    1st                                                                           speed                                                                             o     0                                                                                  ##STR29##  4.143                                                                             0                                               2nd                                                                           speed o   o                                                                                  ##STR30##  1.813                                                                             57                                              3rd                                                                           speed   o o                                                                                  ##STR31##  1.361                                                                             81                                              4th                                                                           speed o o     1.0         1.000                                                                             100                                             Rev.                                                                              o       o                                                                                ##STR32##  -5.984                                                                            0                                               __________________________________________________________________________

In the ninth embodiment shown in FIG. 9, a first planetary gear set X isa dual-intermeshed planet pinion planetary gear set which comprises twofirst sun gears S₁ and S₁ ', a first ring gear R₁ and a first carrier A₁rotatably supporting a plurality of pairs of intermeshing pinions P₁ andP₁ '. Each pinion P₁ meshes with both of the first and second sun gearsS₁ and S₁ ', while each pinion P₁ ' meshes with ring gear R₁. A secondplanetary gear set Y and a third planetary gear set Z are basicplanetary gear sets.

Equations (4), (6) and (5) hold for first, second and third planetarygear sets X, Y and Z of this transmission, respectively.

This transmission comprises an input shaft 1, a hydraulic torqueconverter 3 having a pump 3a connected to the input shaft 1 forsimultaneous rotation therewith and a turbine 3b connected to carrier A₁for simultaneous rotation therewith. Sun gear S₁ is brakeable by meansof a first brake B₁, while, sun gear S₁ ' is connectable to sun gears S₂and S₃ through a first clutch C₁. Sun gears S₂ and S₃ are connected toeach other for simultaneous rotation and are connectable to input shaft1 through a second clutch C₂. Ring gears R₁ and R₂ are connected to eachother for simultaneous rotation and are brakeable by means of a secondbrake B₂. Carrier A₂ and ring gear R₃ are connected to each other forsimultaneous rotation and are connected to output shaft 2 forsimultaneous rotation to provide output torque. Carrier A₃ isconnectable to input shaft 1 through a third clutch C₃.

The operating sequence of three clutches C₁, C₂ and C₃ and two brakes B₁and B₂ of this transmission is tabulated in Table 9 on the assumptionthat α₁ =α₂ =α₃ =0.45.

                                      TABLE 9                                     __________________________________________________________________________                                     Direct                                                                        Trans-                                                                        mission                                                                   Gear                                                                              Rate                                         C.sub.1                                                                             C.sub.2                                                                         C.sub.3                                                                         B.sub.1                                                                         B.sub.2          Ratio                                                                             (%)                                          __________________________________________________________________________    1st                                                                           speed                                                                             o     o                                                                                  ##STR33##     2.636                                                                             0                                            2nd                                                                           speed o   o                                                                                  ##STR34##     1.450                                                                             45                                           3rd                                                                           speed   o o                                                                                  ##STR35##     1.225                                                                             72.5                                         4th                                                                           speed o o     1.0            1.000                                                                             100                                          Rev.                                                                              o       o                                                                                ##STR36##     -2.636                                                                            0                                            __________________________________________________________________________

In the tenth embodiment shown in FIG. 10, a first planetary gear set Xand a third planetary gear set Z are a dual-intermeshed planet pinionplanetary gear set and a basic planetary gear set, respectively, similarto the counterpart shown in FIG. 9, while, a second planetary gear set Yis a dual-intermeshed planet pinion planetary gear set.

Equations (4), (2) and (5) hold for first, second and third planetarygear sets X, Y and Z of this transmission, respectively.

This transmission comprises an input shaft 1, a hydraulic torqueconverter 3 having a pump 3a connected to the input shaft 1 forsimultaneous rotation therewith and a turbine 3b connected to carrier A₁for simultaneous rotation therewith. Sun gear S₁ is brakeable by meansof a first brake B₁. Second sun gear S₁ ' is engageable with carrier A₂through a first clutch C₁, the carrier A₂ and sun gear S₃ beingconnected to each other for simultaneous rotation. Ring gear R₁ and ringgear R₃ are connected to each other for simultaneous rotation and arebrakeable by means of a second brake B₂. Ring gear R₂ is connectable forthe input shaft 1 through a second clutch C₂, while carrier A₂ isconnectable to input shaft 1 through a third clutch C₃. Sun gear S₂ andcarrier A₃ are connected to each other for simultaneous rotation and areconnected to an output shaft 2 for simultaneous rotation and outputtorque production.

The operating sequence of the three clutches C₁, C₂ and C₃ and the twobrakes B₁ and B₂ of the transmission is tabulated in Table 10 on theassumption that α₁ =α₂ =0.60 and α₃ =0.45.

                                      TABLE 10                                    __________________________________________________________________________                                      Direct                                                                        Trans-                                                                        mission                                                                   Gear                                                                              Rate                                        C.sub.1                                                                             C.sub.2                                                                         C.sub.3                                                                         B.sub.1                                                                         B.sub.2           Ratio                                                                             (%)                                         __________________________________________________________________________    1st                                                                           speed                                                                             o     o                                                                                  ##STR37##      3.625                                                                             0                                           2nd                                                                           speed   o o                                                                                  ##STR38##      1.706                                                                             53                                          3rd                                                                           speed o   o                                                                                  ##STR39##      1.393                                                                             74                                          4th                                                                           speed o o     1.0             1.000                                                                             100                                         Rev.                                                                              o       o                                                                                ##STR40##      -4.833                                                                            0                                           __________________________________________________________________________

In the eleventh embodiment shown in FIG. 11, a first planetary gear setX and a second planetary gear set Y are dual-intermeshed planet pinionplanetary gear sets, respectively, while, a third planetary gear set Zis a basic planetary gear set.

Equations (4), (2) and (5) hold for first, second and third planetarygear sets X, Y and Z, respectively.

This transmission comprises an input shaft 1, a hydraulic torqueconverter 3 having a pump 3a connected to the input shaft 1 forsimultaneous rotation therewith and a turbine 3b connected to sun gearS₁ for simultaneous rotation therewith. Carrier A₁ is brakeable by meansof a first brake B₁. Carrier A₂ and sun gear S₃ are connected to eachother for simultaneous rotation and are connectable to carrier A₁through a first clutch C₁, and further are connectable to input shaft 1through a second clutch C₂. Ring gear R₁ and sun gear S₂ are connectedto each other for simultaneous rotation and are brakeable by means of asecond brake B₂. Ring gear R₂ and carrier A₃ are connected to each otherfor simultaneous rotation and are connectable to input shaft 1 through athird clutch C₃. Ring gear R₃ is connected to an output shaft 2 forgenerating output torque.

The operating sequence of three clutches C₁, C₂ and C₃ and two brakes B₁and B₂ of the transmission is tabulated in Table 11 on the assumptionthat α₁ =0.45, α₂ =0.40 and α₃ =0.50.

                                      TABLE 11                                    __________________________________________________________________________                                          Direct                                                                        Trans-                                                                        mission                                                                  Gear Rate                                    C.sub.1                                                                             C.sub.2                                                                         C.sub.3                                                                         B.sub.1                                                                         B.sub.2              Ratio                                                                              (%)                                     __________________________________________________________________________    1st speed                                                                         o     o                                                                                  ##STR41##         3.704                                                                              0                                       2nd speed                                                                           o   o                                                                                  ##STR42##         1.493                                                                              60                                      3rd speed                                                                             o o                                                                                  ##STR43##         1.224                                                                              82                                      4th                                                                           speed o o     1.0                1.000                                                                              100                                     Rev.                                                                              o       o                                                                                ##STR44##         -3.056                                                                             0                                       __________________________________________________________________________

In the twelfth embodiment shown in FIG. 12, this transmission isconstructed of two planetary gear sets X and Y which are basic planetarygear sets, respectively.

Equations (1) and (6) hold for first and second planetary gear sets Xand Y, respectively.

This transmission comprises an input shaft 1, a hydraulic torqueconverter 3 having a pump 3a connected to the input shaft 1 forsimultaneous rotation therewith and a turbine 3b connected to sun gearS₁ for simultaneous rotation therewith. Carrier A₁ is brakeable by meansof a first brake B₁ and is connectable to carrier A₂ through a firstclutch C₁. This carrier A₂ is connected to an output shaft 2 for theoutput torque production. Carrier A₁ is connectable to ring gear R₂through a second clutch C₂. Sun gear S₂ is connected to an output shaft1 for simultaneous rotation therewith. Ring gear R₁ is brakeable bymeans of a second brake B₂ and is connectable to carrier A₂ through athird clutch C₃.

The operating sequence of three clutches C₁, C₂ and C₃ and two brakes B₁and B₂ of this transmission is tabulated in Table 12 on the assumptionthat α₁ =α₂ =0.50.

                                      TABLE 12                                    __________________________________________________________________________                                   Direct                                                                        Trans-                                                                        mission                                                                  Gear Rate                                           C.sub.1                                                                             C.sub.2                                                                         C.sub.3                                                                         B.sub.1                                                                         B.sub.2       Ratio                                                                              (%)                                            __________________________________________________________________________    1st speed                                                                         o       o                                                                                ##STR45##  3.000                                                                              0                                              2nd speed                                                                         o o     o                                                                                ##STR46##  1.800                                                                              60                                             3rd                                                                           speed                                                                             o o       1.0         1.000                                                                              100                                            Rev.    o o                                                                                  ##STR47##  -2.000                                                                             0                                              __________________________________________________________________________

In the operation of the several embodiments of the change speedtransmission, the shift may be made from first through the fourth speedsin an obvious manner illustrated in each of the Tables 1-12. The torquepath in each speed of each embodiment is simply traced through thetransmission by properly considering the noted operative or inoperativecondition of the clutches C₁, C₂ and C₃ and brakes B₁ and B₂. As notedabove in the discussion of each individual embodiment, when a clutch,C₁, C₂ and C₃ is noted as engaged, the two rotary elements are coupledfor simultaneous rotation, and when a brake B₁ and B₂ is noted asapplied, the gear and/or carrier involved is anchored against rotation.

It will now be appreciated that according to the invention, since directtransmission rate is 0% in the first speed or reverse selection, i.e.,all of input torque is transmitted through a torque converter 3, smoothstartup from the standstill is obtained.

It will also be appreciated that according to the invention since thedirect transmission rate is 100% in the highest forward speed selection,i.e., all of the input torque is transmitted through engagement of twoof the clutches C₁, C₂ and C₃ bypassing the torque converter 3,increased efficiency and improved fuel economy at highway speedsequivalent to that obtainable through use of a conventional manualtransmission with a dry disc clutch are realized.

It will also be appreciated that, since a portion of the input torque istransmitted through the torque converter 3 through the middle forwardspeeds, smoothness upon making a shift between adjacent speeds isobtained, as desired, rotational vibration at low speeds is suppressed,and at the same time acceptable fuel economy is obtained.

Therefore, in summary, when the transmission of the invention is used,better shifting performance, smooth riding and good fuel economy areobtained.

It will also be appreciated from this description of the variouspreferred embodiments of the invention, that obvious changes andmodifications can be made without departing from the spirit and scope ofthe invention.

What is claimed is:
 1. A change-speed transmission comprising:an inputmember (1) to receive the input torque; an output member (2) to providethe output torque; a hydrokinetic unit (3) having a pump (3a) connectedto said input member for simultaneous rotation therewith and a turbine(3b); a first and a second and a third clutch (C₁, C₂, C₃); a planetarygear unit (X, Y, Z) having at least a first, a second and a third rotaryelement; said first rotary element of said gear unit being connected tosaid turbine (3b) through said first clutch for simultaneous rotationtherewith when said clutch is engaged; said third rotary element of saidgear unit being connected to said output member for simultaneousrotation therewith; said input member (1) being connected to said secondrotary element through said second clutch (C₂) for simultaneous rotationtherewith when said clutch is engaged; said input member being directlyconnectable through said second and third clutches (C₂, C₃) to saidoutput member (2) for simultaneous rotation therewith so as to bypasssaid hydrokinetic unit when said clutches are simultaneously engaged;whereby the output torque of the transmission may be selectivelyprovided totally through said hydrokinetic unit (3), may be splitpartially through said hydrokinetic unit (3) and partially through atleast one of said second and third clutches thereby providing at least aportion of the output torque to the output member (2) bypassing saidhydrokinetic unit (3) and may be totally provided bypassing saidhydrokinetic unit (3) by actuation of both said second and thirdclutches for increased efficiency.
 2. A change-speed transmission asclaimed in claim 1, in which said planetary gear unit comprises aplurality of planetary gear sets (X, Y, Z) aligned with said input andoutput members; in whichsaid planetary gear unit comprises first, secondand third planetary gear sets each in the form of a dual-intermeshedplanet pinion planetary gear set (X, Y, Z) having a sun gear (S₁, S₂,S₃), a ring gear (R₁, R₂, R₃) and a carrier (A₁, A₂, A₃) with pinions(P₁, P₁ '), (P₂, P₂ '), (P₃, P₃ '), respectively, said sun gear (S₂) assaid first rotary element, said ring gear (R₃) as said third rotaryelement and said carrier (A₁) as said second rotary element, in whichsaid sun gear (S₁) of said first planetary gear set (X) being connectedto said turbine (3b) for simultaneous rotation therewith; said ring gear(R₁) of said first planetary gear set (X), said carrier (A₂) of saidsecond planetary gear set (Y) and said sun gear (S₃) of said thirdplanetary gear set (Z) being connected to one another for simultaneousrotation therewith; said ring gear (R₂) of said second planetary gearset (Y) being connected to said carrier (A₃) of said third planetarygear set (Z) for simultaneous rotation therewith; and said ring gear(R₃) being connected to said output member (2) for simultaneous rotationtherewith; in which said first clutch (C₁) is operable to connect saidsun gear (S₁) of said first planetary gear set (X) to said sun gear (S₂)of said second planetary gear set (Y) for simultaneous rotationtherewith; said second clutch (C₂) is operable to connect with carrier(A₁) of said first planetary gear set (X) to said input member (1); saidthird clutch (C₃) operable to connect said carrier (A₁) of said firstplanetary gear set (X) to said output member (2); and a first brake (B₁)operable to brake said sun gear (S₂) of said second planetary gear set(Y); and a second brake (B₂) operable to brake said ring gear (R₂) ofsaid second planetary gear set (Y) and said carrier (A₃) of said thirdplanetary gear set (Z).
 3. A change-speed transmission as claimed inclaim 1, in which said planetary gear unit comprises a plurality ofplanetary gear sets (X, Y, Z) aligned with said input and outputmembers; in whichsaid planetary gear unit comprises first, second andthird planetary gear sets (X, Y, Z) each in the form of adual-intermeshed planet pinion planetary gear set (X, Y, Z) which has asun gear (S₁, S₂, S₃), a ring gear (R₁, R₂, R₃), and a carrier (A₁, A₂,A₃) with pinions (P₁, P₁ ') (P₂, P₂ ') (P₃, P₃ '), respectively, saidsun gear (S₂) as said first rotary element, said ring gear (R₃) as saidthird rotary element, and said carrier (A₁) as said second rotaryelement, in which said sun gear (S₁) of said first planetary gear set(X) being connected to said turbine (3b) for simultaneous rotationtherewith; said ring gear (R₁) of said first planetary gear set (X) andsaid carrier (A₂, A₃) of said second and third planetary gear sets (Y,Z) being connected to one another for simultaneous rotation therewith;said ring gear (R₂) of said second planetary gear set (Y) beingconnected to said sun gear (S₃) of said third planetary gear set (Z) forsimultaneous rotation therewith; and said ring gear (R₃) of said thirdplanetary gear set (Z) being connected to said output member (2) forsimultaneous rotation therewith; in which said first clutch (C₁) isoperable to connect sun gear (S₁) of said first planetary gear set (X)to said sun gear (S₂) of said second planetary gear set (Y) forsimultaneous rotation therewith; said second clutch (C₂) is operable toconnect said carrier (A₁) of said first planetary gear set (X) to saidinput member (1); and said third clutch (C₃) is operable to connect saidcarrier (A₁) of said first planetary gear set (X) to said output member(2); and a first brake (B₁) operable to brake said sun gear (S₂) of saidsecond planetary gear set (Y) and a second brake (B₂) operable to brakesaid ring gear (R₂) of said second planetary gear set (Y) and said sungear (S₃) of said third planetary gear set (Z).
 4. A change-speedtransmission as claimed in claim 1, wherein the connection between saidturbine (3b) and said first rotary element is further effected throughsaid planetary gear unit;the connection between said input member (1)and said second rotary element is further effected through saidplanetary gear unit; and the direct connection between said input member(1) and said output member (2) is further effected through saidplanetary gear unit.
 5. A change-speed transmission comprising:an inputmember (1) to receive the input torque; an output member (2) to providethe output torque; a hydrokinetic unit (3) having a pump (3a) connectedto said input member for simultaneous rotation therewith and a turbine(3b); a first, a second and a third clutch (C₁, C₂, C₃); a planetarygear unit (X, Y, Z) having at least a first, a second and a third rotaryelement; said first rotary element of said gear unit being selectivelyconnected to said input member (1) through at least one of said firstand second clutches, for simultaneous rotation threrewith when theselected clutch is engaged; said second rotary element of said gear unitbeing connectable through said third clutch (C₃) to said input member(1) for simultaneous rotation therewith when said clutch is engaged;said output member (2) being connected to said third rotary element ofsaid gear unit for simultaneous rotation therewith; said input memberbeing connectable through said clutches to said third rotary element forsimultaneous rotation therewith so as to totally bypass saidhydrokinetic unit when at least two of said clutches are engaged;whereby the output torque of the transmission may be selectivelyprovided totally through said hydrokinetic unit (3), may be splitpartially through said hydrokinetic unit (3) and partially through atleast one of said second and third clutches thereby providing at least aportion of the output torque to the output member (2) bypassing saidhydrokinetic unit (3) and may be totally provided bypassing saidhydrokinetic unit (3) by actuation of at least two of said clutches forincreased efficiency.
 6. A change-speed transmission as claimed in claim5, in which said planetary gear unit comprises aplurality of planetarygear sets (X, Y, Z) aligned with said input and output members; in whichsaid first and second planetary gear sets each including adual-intermeshed planet pinion planetary gear set (X, Y) which has a sungear (S₁, S₂), a ring gear (R₁, R₂) and a carrier (A₁, A₂) with pinions(P₁, P₁ ') (P₂, P₂ '), respectively; a third planetary gear set in theform of a basic planetary gear set (Z) which has a sun gear (S₃), a ringgear (R₃) and a carrier (A₃) with pinion (P₃), said carrier (A₂) as saidfirst rotary element, said ring gear (R₃) as said second rotary element,and said carrier (A₃) as said third rotary element, in which said sungear (S₁) of said first planetary gear set (X) is connected to saidturbine (3b) for simultaneous rotation therewith; said carrier (A₁) ofsaid first planetary gear set (X) is connected to said sun gear (S₂) ofsaid second planetary gear set (Y) for simultaneous rotation therewith;said ring gear (R₁) of said first planetary gear set (X) is connected tosaid sun gear (S₃) of said third planetary gear set (Z); and said ringgears (R₂, R₃) of said second and third planetary gear sets (Y, Z) areconnected to each other for simultaneous rotation; and said carrier (A₃)of said third planetary gear set (Z) is connected to said output member(2) for simultaneous rotation therewith; in which said first clutch (C₁)is operable to connect said ring gear (R₁) of said first planetary gearset (X) and said sun gear (S₃) of said third planetary gear set (Z) tosaid carrier (A₂) of said second planetary gear set (Y) for simultaneousrotation therewith; said second clutch (C₂) is operable to connect saidcarrier (A₂) of said second planetary gear set (Y) to said input member(1) for simultaneous rotation therewith; and said third clutch (C₃) isoperable to connect said ring gears (R₂, R₃) of said second and thirdplanetary gear sets (Y, Z) to said input member (1) for simultaneousrotation therewith; and in which a first brake (B₁) operable to brakesaid carrier (A₁) of said first planetary gear set (X) and said sun gear(S₂) of said second planetary gear set (Y), and a second brake (B₂)operable to brake said ring gear (R₁) of said first planetary gear set(X) and said sun gear (S₃) of said third planetary gear set (Z).
 7. Achange-speed transmission as claimed in claim 5, in which said planetarygear unit comprises aplurality of planetary gear sets aligned with saidinput and output members; in which a first planetary gear set in theform of a dual-intermeshed planet pinion planetary gear set (X) whichhas a sun gear (S₁), a ring gear (R₁) and a carrier (A₁) with pinion(P₁, P₁ '); and second and third planetary gear sets each in the form ofa basic planetary gear set (Y, Z) which has a sun gear (S₂, S₃), a ringgear (R₂, R₃) and a carrier (A₂, A₃) with pinion (P₂) (P₃),respectively, said sun gear (S₂) as said first rotary element, said ringgear (R₃) as said second rotary element, and said carrier (A₃) as saidthird rotary element, in which said sun gear (S₁) of said firstplanetary gear set (X) is connected to said turbine (3b) forsimultaneous rotation therewith; said ring gears (R₁,R₂) of said firstand second planetary gear sets (X, Y) and said sun gear (S₃) of saidthird planetary gear set (Z) are connected to one another forsimultaneous rotation therewith; and said carriers (A₂, A₃) of saidsecond and third planetary gear sets (Y, Z) are connected to said outputmember (2) for simultaneous rotation therewith; in which said firstclutch (C₁) is operable to connect said carrier (A₁) of said firstplanetary gear set (X) to said sun gear (S₂) of said second planetarygear set (Y) for simultaneous rotation therewith; said second clutch(C₂) is operable to connect said sun gear (S₂) of said second planetarygear set (Y) to said input member (1) for simultaneous rotationtherewith; and said third clutch (C₃) is operable to connect said ringgear (R₃) of said third planetary gear set (Z) to said input member (1)for simultaneous rotation therewith; and in which a first brake (B₁)operable to brake said carrier (A₁) of said first planetary gear set(X); and a second brake (B₂) operable to brake said ring gears (R₁, R₂)of said first and second planetary gear sets (X, Y) and said sun gear(S₃) of said third planetary gear set (Z).
 8. A change-speedtransmission as claimed in claim 5, in which said planetary gear unitcomprises aplurality of planetary gear sets aligned with said input andoutput members; in which first and third planetary gear sets each in theform of a dual-intermeshed planet pinion planetary gear set (X, Y) whichhas a sun gear (S₁, S₃), a ring gear (R₁, R₃), and a carrier (A₁, A₃)with pinions (P₁, P₁ ') (P₃, P₃ '), respectively; and a second planetarygear set in the form of a basic planetary gear set (Y) which has a sungear (S₂), a ring gear (R₂), and a carrier (A₂) with pinion (P₂); inwhich said sun gear (S₃) as said first rotary element, said ring gear(R₂) as said second rotary element, and carrier (A₂) as said thirdrotary element; said sun gear (S₁) of said first planetary gear set (X)is connected to said turbine (3b) for simultaneous rotation therewith;said ring gear (R₁) of said first planetary gear set (X), said sun gear(S₂) of said second planetary gear set (Y) and said carrier (A₃) of saidthird planetary gear set (Z) are connected to one another forsimultaneous rotation therewith; said ring gear (R₂) of said secondplanetary gear set (Y) and said ring gear (R₃) of said third planetarygear set (Z) are connected to each other for simultaneous rotationtherewith; and said carrier (A₂) of said second planetary gear set (Y)is connected to said output member (2) for simultaneous rotationtherewith; in which said first clutch (C₁) is operable to connect saidcarrier (A₁) of said first planetary gear set (X) to said sun gear (S₃)of said third planetary gear set (Z) for simultaneous rotationtherewith; said second clutch (C₂) is operable to connect said sun gear(S₃) of said third planetary gear set (Z) to said input member (1) forsimultaneous rotation therewith; and said third clutch (C₃) is operableto connect said ring gears (R₂, R₃) of said second and third planetarygear sets (Y, Z) to said input member (1) for simultaneous rotationtherewith; and in which a first brake (B₁) operable to brake saidcarrier (A₁) of said first planetary gear set (X); and a second brake(B₂) operable to brake said ring gear (R₁) of said first planetary gearset (X), said sun gear (S₂) of said second planetary gear set (Y) andsaid carrier (A₃) of said third planetary gear set (Z).
 9. Achange-speed transmission as claimed in claim 5, in which said planetarygear unit comprises aplurality of planetary gear sets aligned with saidinput and output members; in which first and second planetary gear setseach in the form of a dual-intermeshed planet pinion planetary gear set(X, Y) which has a sun gear (S₁, S₂), a ring gear (R₁, R₂) and a carrier(A₁, A₂) with pinion (P₁, P₁ ') (P₂, P₂ '), respectively, and a thirdplanetary gear set in the form of a basic planetary gear set (Z) whichhas a sun gear (S₃), a ring gear (R₃) and a carrier (A₃) with pinion(P₃); in which said carrier (A₂) as said first rotary element, said ringgear (R₂) as said second rotary element, and carrier (A₃) as said thirdrotary element; said sun gear (S₁) of said first planetary gear set (X)is connected to said turbine (3b) for simultaneous rotation therewith;said ring gears (R₁, R₃) of said first and third planetary gear sets (X,Z) and said sun gear (S₂) of said second planetary gear set (Y) areconnected to one another for simultaneous rotation therewith; saidcarrier (A₂) of said second planetary gear set (Y) is connected to saidsun gear (S₃) of said third planetary gear set (Z) for simultaneousrotation therewith; and said carrier (A₃) of said third gear set (Z) isconnected to said output member (2) for simultaneous rotation therewith;in which said first clutch (C₁) is operable to connect said carrier (A₁)of said first planetary gear set (Z) to said carrier (A₂) of said secondplanetary gear set (Y) and said sun gear (S₃) of said third planetarygear set (Z) for simultaneous rotation therewith; said second clutch(C₂) is operable to connect said carrier (A₂) of said second planetarygear set (Y) and said sun gear (S₃) of said third planetary gear set (Z)to said input member (1) for simultaneous rotation therewith; and saidthird clutch (C₃) is operable to connect said ring gear (R₂) of saidsecond planetary gear set (Y) to said input member (1) for simultaneousrotation therewith; and in which a first brake (B₁) operable to brakesaid carrier (A₁) of said first planetary gear set (X); and a secondbrake (B₂) operable to brake said ring gear (R₁) of said first planetarygear set (X), said sun gear (S₂) of said second planetary gear set (Y)and said ring gear (R₃) of said third planetary gear set (Z).
 10. Achange-speed transmission as claimed in claim 5, in which said planetarygear unit comprises aplurality of planetary gear sets aligned with saidinput and output members; in which a first planetary gear set in theform of a dual-intermeshed planet pinion planetary gear set (X) whichhas a sun gear (S₁), a ring gear (R₁) and a carrier (A₁) with pinion(P₁, P₁ '); and second and third planetary gear sets each in the form ofa basic planetary gear set (Y, Z) which has a sun gear (S₂, S₃), a ringgear (R₂, R₃) and a carrier (A₂, A₃) with pinion (P₂) (P₃),respectively, in which said sun gear (S₂) as said first rotary element,said carrier (A₃) as said second rotary element, and said ring gear (R₃)as said third rotary element; said sun gear (S₁) of said first planetarygear set (X) is connected to said turbine (3b) for simultaneous rotationtherewith; said sun gears (S₂, S₃) of said second and third planetarygear sets (Y, Z) are connected to each other for simultaneous rotationtherewith; said ring gears (R₁, R₂) of said first and second planetarygear sets (X, Y) are connected to each other for simultaneous rotationtherewith; and said carrier (A₂) of said second planetary gear set (X)and said ring gear (R₃) of said third planetary gear set (Z) areconnected to said output member (2) for simultaneous rotation therewith;in which said first clutch (C₁) is operable to connect said carrier (A₁)of said first planetary gear set (X) to said sun gears (S₂, S₃) of saidsecond and third planetary gear sets (Y, Z) for simultaneous rotationtherewith; said second clutch (C₂) is operable to connect said sun gears(S₂, S₃) of said second and third planetary gear sets (Y, Z) to saidinput member (1) for simultaneous rotation therewith; and said thirdclutch (C₃) is operable to connect said carrier (A₃) of said thirdplanetary gear set (Z) to said input member (1) for simultaneousrotation therewith; in which a first brake (B₁) operable to brake saidcarrier (A₁) of said first planetary gear set (X); and a second brake(B₂) operable to brake said ring gears (R₁, R₂) of said first and secondplanetary gear sets (X, Y).
 11. A change-speed transmission as claimedin claim 5, in which said planetary gear unit comprises aplurality ofplanetary gear sets aligned with said input and output members; in whicha first planetary gear set in the form of a dual-intermeshed planetpinion planetary gear set (X) which has first and second sun gears (S₁,S₁ '), a ring gear (R₁) and a carrier (A₁) with pinion (P₁, P₁ '); andsecond and third planetary gear sets each in the form of a basicplanetary gear set (Y, Z) which has a sun gear (S₂, S₃), a ring gear(R₂, R₃) and a carrier (A₂, A₃) with pinion (P₂)(P₃), respectively, inwhich said sun gear (S₃) as said first rotary element, said carrier (A₃)as said second rotary element, and ring gear (R₃) as said third rotaryelement; said carrier (A₁) of said first planetary gear set (X) isconnected to said turbine (3b) for simultaneous rotation therewith; saidring gears (R₁, R₂) of said first and second planetary gear sets (X, Y)are connected to each other for simultaneous rotation therewith; saidsun gears (S₂, S₃) of said second and third planetary gear sets (Y, Z)are connected to each other for simultaneous rotation therewith; andsaid carrier (A₂) of said second planetary gear set (Y) and said ringgear (R₃) of said third planetary gear set (Z) are connected to saidoutput member (2) for simultaneous rotation therewith; in which saidfirst clutch (C₁) is operable to connect said second sun gear (S₁ ') ofsaid first planetary gear set (X) to said sun gears (S₂, S₃) of saidsecond and third planetary gear sets (Y, Z) for simultaneous rotationtherewith; said second clutch (C₂) is operable to connect said sun gears(S₂, S₃) of said second and third planetary gear sets (Y, Z) to saidinput member (1) for simultaneous rotation therewith; said third clurch(C₃) is operable to connect said carrier (A₃) of said third planetarygear set (Z) to said input member (1) for simultaneous rotationtherewith; and in which a first brake (B₁) operable to brake said firstsun gear (S₁) of said first planetary gear set (X); and a second brake(B₂) operable to brake said ring gears (R₁, R₂) of first and secondplanetary gear sets (X, Y).
 12. A change-speed transmission as claimedin claim 5, in which said planetary gear unit comprises aplurality ofplanetary gear sets aligned with said input and output members; in whicha first planetary gear set in the form of a dual-intermeshed planetpinion planetary gear set (X) which has first and second sun gears (S₁,S₁ '), a ring gear (R₁) and a carrier (A₁) with pinion (P₁, P₁ '); asecond planetary gear set in the form of a dual-intermeshed planetpinion planetary gear set (Y) which has a sun gear (S₂), a ring gear(R₂) and a carrier (A₂) with pinion (P₂, P₂ '); and a third planetarygear set in the form of a basic planetary gear set (Z) which has a sungear (S₃), a ring gear (R₃) and a carrier (A₃) with pinion (P₃); inwhich said carrier (A₂) as said first rotary element, said sun gear (S₃)as said second rotary element, and said carrier (A₃) as said thirdrotary element; said carrier (A₁) of said first planetary gear set (X)is connected to said turbine (3b) for simultaneous rotation therewith;said ring gears (R₁, R₃) of said first and third planetary gear sets(A₁, A₃) are connected to each other for simultaneous rotationtherewith; said carrier (A₂) of said second planetary gear set (Y) isconnected to said sun gear (S₃) of said third planetary gear set (Z) forsimultaneous rotation therewith; and said sun gear (S₂) of said secondplanetary gear set (Y) and said carrier (A₃) of said third planetarygear set (Z) are connected to said output member (2) for simultaneousrotation therewith; in which said first clutch (C₁) is operable toconnect said second sun gear (S₁ ') of said first planetary gear set (X)to said carrier (A₂) of said second planetary gear set (Y) and said sungear (S₃) of said third planetary gear set (Z) for simultaneous rotationtherewith; said second clutch (C₂) is operable to connect said ring gear(R₂) of said second planetary gear set (Y) to said input member (1) forsimultaneous rotation therewith; and said third clutch (C₃) is operableto connect said carrier (A₂) of said second planetary gear set (Y) tosaid input member (1) for simultaneous rotation therewith; in which afirst brake (B₁) operable to brake said first sun gear (S₁) of saidplanetary gear set (X); and a second brake (B₂) operable to brake saidring gears (R₁, R₃) of said first and third planetary gear sets (X, Z).13. A change-speed transmission as claimed in claim 5, in which saidplanetary gear unit comprises aplurality of planetary gear sets alignedwith said input and output members; in which first and second planetarygear sets each in the form of a dual-intermeshed planet pinion planetarygear set (X, Y) which has a sun gear (S₁, S₂), a ring gear (R₁, R₂) anda carrier (A₁, A₂) with pinion (P₁, P₁ ') (P₂, P₂ '), respectively, anda third planetary gear set in the form of a basic planetary gear set (Z)which has a sun gear (S₃), a ring gear (R₃) and a carrier (A₃) withpinion (P₃); in which said sun gear (S₃) as said first rotary element,said carrier (A₃) as said second rotary element, and ring gear (R₃) assaid third rotary element; said sun gear (S₁) of said first planetarygear set (X) is connected to said turbine (3b) for simultaneous rotationtherewith; said ring gear (R₁) of said first planetary gear set (X) isconnected to said sun gear (S₂) of said second planetary gear set (Y)for simultaneous rotation therewith; said carrier (A₂) of said secondplanetary gear set (Y) is connected to said sun gearm (S₃) of said thirdplanetary gear set (Z) for simultaneous rotation therewith; said ringgear (R₂) of said second planetary gear set (Y) is connected to saidcarrier (A₃) of said third planetary gear set (Z) for simultaneousrotation therewith; and said ring gear (R₃) of said third planetary gearset (Z) is connected to said output member (2) for simultaneous rotationtherewith; in which said first clutch (C₁) is operable to connect saidcarrier (A₁) of said first planetary gear set (X) to said carrier (A₂)of said second planetary gear set (Y) and said sun gear (S₃) of saidthird planetary gear set (Z) for simultaneous rotation therewith; saidsecond clutch (C₂) is operable to connect said carrier (A₂) of saidsecond planetary gear set (Y) and said sun gear (S₃) of said thirdplanetary gear set (Z) to said input member (1) for simultaneousrotation therewith; and said third clutch (C₃) is operable to connectsaid carrier (A₃) of said third planetary gear set (Z) and said ringgear (R₂) of said second planetary gear set (Y) to said input member (1)for simultaneous rotation therewith; in which a first brake (B₁)operable to brake said carrier (A₁) of said first planetary gear set(X); and a second brake (B₂) operable to brake said ring gear (R₁) ofsaid first planetary gear set (X) and said sun gear (S₂) of said secondplanetary gear set (Y).
 14. A change-speed transmission comprising:aninput member (1) to receive the input torque; an output member (2) toprovide the output torque; a hydrokinetic unit (3) having a pump (3a)connected to said input member for simultaneous rotation therewith and aturbine (3b); a first and a second and a third clutch (C₁, C₂, C₃); aplanetary gear unit (X, Y) having at least a first, a second and a thirdrotary element; said planetary gear unit comprising first and secondplanetary gear sets each in the form of a basic planetary gear set (X,Y) which has a sun gear (S₁, S₂), a ring gear (R₁, R₂) and a carrier(A₁, A₂) with pinion (P₁)(P₂), respectively; in which said sun gear (S₁)of said first planetary gear set (X) is connected to said turbine (3b)for simultaneous rotation therewith; said sun gear (S₂) of said secondplanetary gear set (Y) is connected to said input member (1) forsimultaneous rotation therewith; and said carrier (A₂) of said secondplanetary gear set (Z) is connected to said output member (2) forsimultaneous rotation therewith; and in which said first clutch (C₁) isoperable to connect said carrier (A₁) of said first planetary gear set(X) to said carrier (A₂) of said second planetary gear set (Y) forsimultaneous rotation therewith; a second clutch (C₂) operable toconnect said carrier (A₁) of said first planetary gear set (X) to saidring gear (R₂) of said second planetary gear set (Y) for simultaneousrotation therewith; a third clutch (C₃) is operable to connect said ringgear (R₁) of said first planetary gear set to said output member (2) forsimultaneous rotation therewith; and in which a first brake (B₁)operable to brake said carrier (A₁) of said first planetary gear set(X); and a second brake (B₂) operable to brake said ring gear (R₁) ofsaid first planetary gear set (X).
 15. A change-speed transmissioncomprising:an input member (1) to receive the input torque; an outputmember (2) to provide the output torque; a planetary gearing unit havinga plurality of planetary gear sets, each having at least three rotaryelements including a sun gear, a ring gear and a carrier with pinion; ahydrokinetic unit (3) having a pump (3a) connected to said input member(1) for simultaneous rotation therewith and a turbine (3b) connected tosaid planetary gearing unit; and at least three clutch means (C₁, C₂,C₃) and at least two brake means (B₁, B₂) operable to shift saidplanetary gearing unit into a condition in which all of torque of saidinput member is transmitted to said output member through saidhydrokinetic unit (3) and said planetary gearing unit to provide thehighest reduction gear ratio of all forward speeds, operable to shiftsaid planetary gearing unit into a condition in which all of the torqueof said input member (1) is transmitted to said output member (2)bypassing said hydrokinetic unit (3) to provide direct drive to saidoutput member, and further operable to shift said planetary gearing unitinto a condition in which a portion of the torque of said input member(1) is transmitted to said output member (2) bypassing said hydrokineticunit (3), and the remaining portion of the torque of said input member(1) is transmitted to said output member (2) through said hydrokineticunit (3) to provide at least one intermediate reduction gear ratio ofthe forward speeds, whereby the output torque of the transmission may beselectively provided totally through said hydrokinetic unit (3), may besplit partially through said hydrokinetic unit (3) and partially throughat least one of said second and third clutches thereby providing atleast a portion of the output torque to the output member (2) bypassingsaid hydrokinetic unit (3) and may be totally provided bypassing saidhydrokinetic unit (3) by actuation of at least two of said clutches forincreased efficiency.
 16. A change-speed transmission comprising:aninput member (1) to receive the input torque; an output member (2) toprovide the output torque; a hydrokinetic unit (3) having a pump (3a)connected to said input member for simultaneous rotation therewith and aturbine (3b); a first and a second and a third clutch (C₁, C₂, C₃); aplanetary gear unit (X, Y, Z) having at least a first, a second and athird rotary element; said planetary gear unit comprising a plurality ofplanetary gear sets (X, Y, Z) aligned with said input and outputmembers; in which said first planetary gear set (X) having a sun gear(S₁) as said first rotary element, a ring gear (R₁) and a carrier (A₁)with pinion (P₁); and second and third planetary gear sets (Y, Z) eachin the form of a dual-intermeshed planet pinion planetary gear set whichhas a sun gear (S₂, S₃), a ring gear (R₂, R₃) and a carrier (A₂, A₃),with pinion (P₂ ', P₃ '), respectively, said sun gear (S₁) as said firstrotary element, said ring gear (R₃) as said second rotary element andsaid carrier (A₃) as said third rotary element, in which said carrier(A₂) of said second planetary gear set (Y) being connected to saidturbine (3b); said sun gear (S₂) of said second planetary gear set (Y)being connected to said sun gear (S₁) of said first planetary gear set(X) for simultaneous rotation therewith; said ring gear (R₁) of saidfirst planetary gear set (X) being connected to said ring gear (R₃) ofsaid third planetary gear set (Z) for simultaneous rotation therewithand being connected to said output number (2) for simultaneous rotationtherewith; and said ring gear (R₂) of said second planetary gear set (Y)being connected to said sun gear (S₃) of said third planetary gear set(Z) for simultaneous rotation therewith; and in which said first clutch(C₁) being operable to connect said sun gears (S₁, S₂) of said first andsecond planetary gear sets (X, Y) to said carrier (A₂) of said secondplanetary gear set (Y) for simultaneous rotation therewith; said secondclutch (C₂) being operable to connect said carrier (A₃) of said thirdplanetary gear set (Z) to said input member (1) for simultaneousrotation therewith; and said third clutch (C₃) being operable to connectsaid carrier (A₃) of said third planetary gear set (Z) to said outputmember (2) for simultaneous rotation therewith; and a first brake (B₁)operable to brake said sun gears (S₁, S₂) of said first and secondplanetary gear sets (X, Y) and a second brake (B₂) operable to brakesaid carrier (A₁) of said first planetary gear set (X).